Starter-alternators are electric machines which function as both motors and generators, and are employed within vehicles to provide electrical power and torque. Particularly, starter-alternators are typically used within hybrid-electric type vehicles, and provide a variety of functions and benefits, including but not limited to generating and providing electrical power to vehicle systems and components; starting the vehicle's engine; providing additional torque to the vehicle's engine during heavy accelerations; assisting in and/or performing the braking functions of the vehicle, thereby capturing the kinetic energy of the moving vehicle; and stopping or "shutting off" the vehicle's engine during idling and decelerating states or conditions, thereby improving the overall fuel economy of the vehicle.
Starter-alternators are typically and operatively disposed in the space or area normally occupied by a flywheel an d a clutch, in the case of manual transmission type vehicles, or by a torque converter, in the case of automatic transmission type vehicles . Starter-alternators generally include a stator, which is fixedly coupled to the vehicle's engine block, and a rotor which is coupled to the vehicle's crankshaft, and which is rotatably disposed within the stator. Particularly, the rotor is concentrically disposed with respect to the stator, and is separated from the stator by a relatively uniform, precise and minute gap or space, across which magnetic flux generated by the two assemblies traverses or travels.
One drawback associated with these starter-alternators is that the relatively uniform, precise and minute gap between the stator and the rotor is relatively difficult to create and/or form during the installation and/or assembly procedures. Another drawback associated with these starter-alternators is that they do not accommodate or compensate for axial loads which are generated by internal combustion forces of the engine, which are transferred to the electric machines by way of the crankshaft. These axial loads cause undesirable stress and/or wear to the crankshaft and to the components of the electrical machine. Additionally, oil and/or lubricant, which is contained within the engine block, may leak outside of the engine block and into the space or area occupied by the starter-alternator, thereby undesirably contacting components and/or portions of the starter-alternator.
Attempts have been made to maintain the precision and uniformity of the relatively small gap between the stator and the rotor, to reduce the axial loads imparted on the crankshaft, and to prevent the leakage of oil and/or lubricant from the engine block. For example and without limitation, attempts have been made to manually align and/or center the rotor and the stator during the installation procedure, by the use of manual alignment tools or devices. However, these types of manual alignment procedures are undesirably time-consuming and tedious. Additionally, such alignment procedures do not significantly reduce the axial loads transferred to the crankshaft by the substantially unsupported rotor. Other attempts have been made to tighten the specifications and/or tolerances of the components of the starter-alternator and/or of the crankshaft. These prior attempts have undesirably and significantly increased the overall cost of the assembly, and have not provided substantial improvement in maintaining the small and uniform gap, in reducing the stress imparted on the crankshaft, or in reducing the space required for oil retaining components.
There is therefore a need for a new and improved method and apparatus for installing a starter-alternator within a vehicle which overcomes many, if not all, of the previously delineated drawbacks of such prior methods and devices.